1. Field of the Invention
The present invention relates to a video scope which comprises a solid-state image pickup device such as a CCD.
2. Related art of the Invention
In the recent years, video scopes which utilize CCDs are used in fields of dental surgery and oral surgery for diagnosing affected parts in oral cavities. Such video scopes are classified into two types: one which transmits an illumination rays beam through optical fibers and leads an image of an object to be observed through transfer means such as a lens to a solid-state image pickup device disposed outside an oral cavity like a video scope disclosed by Japanese Patent Application Laid-Open No. 4-176436 and the other type which leads an image of an object to be observed through image fibers to a solid-state image pickup device disposed outside an oral cavity like a video scope disclosed by Japanese Patent Application Laid-Open No. 62-246347.
According to a conventional art disclosed by Japanese Patent Application Laid-Open No. 4-176436, optical fibers used in a light leading path for illumination require disposing lenses and prisms to condense rays onto a section of incidence and project rays to a projector window, and must be disposed in complicated forms so that they are accommodated in a video scope. However, optical fibers which are apt to be easily broken when bent steeply can hardly be stretched to a tip of a video scope and this conventional art hardly allows a number of required parts to be reduced.
Further, this conventional art is configured to connect an electric cable from an external camera circuit to a grip section of a video scope body and connect a optical fiber cable from an external light source box to the grip section, thereby making the video scope equipped with two cables, heavy and low in operability thereof. Further, there is available an electric cable which has built-in optical fibers and is formed as a single cord. When such a cord which is thick and long is connected to a grip section of a video scope body, however, it degrades operability of a video scope or makes it rather inconvenient for handling like the plurality of cables.
Furthermore, a conventional art disclosed by Japanese Patent Application Laid-Open No. 62-246347 or No. 4-176436 is configured to dispose an image pickup device not in a tip to be located in the vicinity of an oral cavity but in a rear section such as a grip section, thereby requiring image transfer means such as image fibers or a lens which has a long optical path. However, the image transfer means such as image fibers or a lens having a long optical path makes a video scope complicated in structure and expensive.
In view of the problems described above, a primary object of the present invention is to provide a video scope which is simple, easy to handle and inexpensive enough for domestic use while requiring no external camera circuit, external power source, external light source or light leading path for illumination.
Apart from the discussion made above, it is emphasized to find and treat decayed teeth in early stages along with a movement to leave 20 teeth at an age of 80 which is promoted by the Ministry of Health and Welfare, etc. Under the current circumstances, babies and children are checked for decayed teeth at health centers and schools, and subjected to treatments after their decayed are pointed out, whereas adult people have small occasions of dental inspection and generally go to dentist's after they feel toothache. In such cases, teeth are badly decayed, thereby requiring many days and high costs for treatments. For checking conditions of teeth at home, it is general to observe the teeth with a single mirror or a combination of such a mirror and a commercially available dental mirror which has a small diameter. However, it is difficult to find decayed teeth at early stages since a single mirror hardly serves for observing sides and rear surfaces of teeth at the back, and even a dental mirror which has a small diameter is ineffective to understand complicated occulusions and cannot provide magnified images. It is therefore demanded to obtain a domestic video scope which is inexpensive and easy to use.
Though a video scope must be strictly sterilized before use, it is not easy to sterilize its portion which comprises an optical mechanism and, it is remarkably difficult from viewpoints of technique and time to completely sterilize even a business video scope which is used by dentists each time an operator shifts to another.
It is much more difficult to sterilize a video scope in a home environment. Even within a family, articles which are used in oral cavities such as tooth brushes are prepared not for common use but for individual use. It is a problem to use a video scope which has not been sterilized even if it has been washed.
Therefore, a cover or the like is fitted over an video signal input section of a video scope. However, people judge a cover as in sanitary from a fear that a thin cover such as a vinyl sack may be broken or that saliva may penetrate through a cover.
When a cover is only fitted over the video signal input section, it is fearful that the cover comes off during use and constitutes a risk of penetration into a throat.
In view of the problems described above, another object of the present invention is to provide a safe video scope which is free from hygienic concerns as injection and accident of dropping of a cover.